Tens of thousands of Slovaks have taken part in rallies to honor a 27-year-old investigative journalist shot dead last week along with his partner.

In the capital of Bratislava, President Andrej Kiska asked a crowd estimated at 25,000 people to observe a minute of silence for Jan Kuciak and his girlfriend, Martina Kusnirova, whose bodies were found on February 25 in their house in Velka Maca, east of the capital, Bratislava.

They had both been shot.

Thousands showed up in 25 other cities and towns across the EU country of 5.4 million people, and in cities abroad, including London, Paris, and Brussels. Many held candles, marching in silence in subzero weather.

Similar marches were being held in some 25 towns and cities across the country and in cities abroad, including London, Paris, and Brussels.

Alongside photos of the journalist, demonstrators in Bratislava displayed banners saying, "I am angry," ''Mafia get out of my country," and "An attack on journalists = an attack on us all."

Kuciak's last, unfinished story was about the activities of the Italian Mafia in eastern Slovakia and their ties to people close to Prime Minister Robert Fico.

The killings prompted demands from Fico's coalition partners for the resignation of senior officials.

The seven suspects were detained during raids in seven locations in eastern Slovakia.

Gaspar identified the detainees by their first names and initials and some of these appeared to match names of Italian businesspeople who were the focus of Kuciak's final report.

Gaspar said one of the detainees was Antonino V.

According to the Slovak business registry, Italian businessman Antonino Vadala briefly owned a firm with Maria Troskova, a former model and an aide to Fico.

Troskova and the secretary of the country's Security Council, also mentioned in Kuciak's reporting, resigned on February 28 pending results of the investigation. Both Troskova and the secretary have denied any wrongdoing.

Roberti said on Italian radio: "We warned authorities in Bratislava, but unfortunately they didn't heed us" about the 'Ndrangheta syndicate's expansion into Slovakia.

He said the 'Ndrangheta, based in southern Italy, might have killed Kuciak and his partner in Slovakia because "there was no other way to silence" him.

Meanwhile, global media watchdog Reporters Without Borders (RSF) on March 2 warned EU leaders against undermining the security of journalists in the wake of Kuciak's murder.

The Slovak investigative reporter's assassination came just months after journalist Daphne Caruana Galizia was killed in a car bombing in Malta after exposing crime and corruption on the Mediterranean island.

Investigators in both murders are probing links to organized crime, but RSF said some EU leaders could also be endangering members of the media through public slurs.

Christophe Deloire, the RSF secretary-general, said some European politicians, including government leaders, have sustained and even created an "appalling climate for journalists."

"European leaders have a responsibility to defend journalism and not to weaken it," he added.

Deloire also said he asked Fico, whom he met in Bratislava on March 2, to "clearly express his regrets" for having publicly insulted journalists.

"Insulting journalists, denials of the legitimacy of journalism by high-level politicians are dangerous to journalists," Deloire said.

Fico's office later issued a statement saying that there was "no call on the PM to apologize to journalists," denying Deloire's claim.

Fico once told journalists they were "dirty, anti-Slovak whores" and labeled the media as being "plain, silly hyenas" and "slimy snakes."

The RSF head also pointed to other Central European leaders like Czech President Milos Zeman and governing parties in Hungary and Poland as generating a hostile environment for the media that threatens the security of journalists and press freedom in general.

"The Czech president last year showed up at a press conference with a toy Kalashnikov in his hand labeled 'For Journalists'," Deloire said of an incident in October.

Deloire also said that ruling parties in Poland and Hungary "have reduced pluralism" in public broadcasters, turning them into mouthpieces for the political power.